In tests call ImeAdapter from UI thread only.

BUG=None
R=tedchoc@chromium.org

Review URL: https://codereview.chromium.org/191133003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255718 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255718
Change screenshots from default opt-in to default opt-out.

R=xiyuan@chromium.org
BUG=350484

Review URL: https://codereview.chromium.org/189833007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255719 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255719